Unfortunately as an investigative reporter I have had to use subterfuge many times to get at the truth.

Over the years I have worn hidden cameras, posed as a long-lost relative, secretly recorded people, and kept a whirring tape recorder in my bag.

I have even presented myself on the doorstep of an interviewee knowing she thought I was a policeman, in order to get the information needed – although I stress I have never impersonated a police officer as this is against the law.

Bizarrely when I was working for BBC Panorama long before my HSP set in, I rang up a leading Cardiff barrister for a quote and NOT recording the conversation, he said: “This is being recorded”.

So I replied: “No don’t worry – I am not recording”.

Secret recording devices can be hot!

“No”, he said. “I AM recording it”!

This remarkable interchange stresses that the line between comedy and drama is very finely drawn, and on the same Panorama programme I was treated to more classic examples of this.

To record one particular interview (with a serving and potentially murderous police officer) I wore a hidden camera in my tie which became very hot.

If the interviewee had sat here the shot would have been useless

I kept having to move my tie otherwise the heat would have become unbearable on my chest!

The interview was being conducted at a safe location in Neath where I knew the windows were on one side.

I hared up the stairs with my producer in order to sit with my back to the window so the police officer would have to take the seat with his back to the wall and the light on him.

I knew that if he had taken the seat next to the window, the light behind him would have rendered the shot useless.

There was never a recording device here!

I remember thinking to myself this is so ridiculous it would make a brilliant sit-com!

In order to do any secret filming at The BBC you had to surmount all sorts of bureaucratic hurdles and get the agreement of your Editor.

On that BBC Panorama programme, both my producer and I were wearing hidden tie cameras, but his broke down so we were reliant on mine which thankfully kept working despite my repeated moving of the tie!

My producer wore glasses and he told me once that interviewees often thought a recording device was fitted into his spectacles case!

Knowing these techniques brings reward

It never was.

You will be glad to know we secured the interview with the police officer and he effectively confessed to murder.

Knowledge of how to do these sort of things legally is almost as important for journalists as knowing the libel laws.